This invention relates in general to electrotherapy apparatus and, more specifically, to a device that combines a neuromuscular stimulator for electrically stimulating muscles and an electromyograph for measuring the stimulation and its affects.
A wide variety of devices have been developed for applying a low intensity direct alternating current to the skin to stimulate muscles or nerves, to relieve pain, etc. Typical of these are the nerve stimulation devices described by Hudleson et al. in U.S. Pat. No. 4,232,680, Takeuchi et al. in U.S. Pat. 4,895,153 and Kenyon et al. in U.S. Pat. No. 4,723,552. Electrical energy has also been introduced into the skin to relieve sinus and nasal congestion as described by Claude et al. in U.S. Pat. No. 4,926,880 and to treat skin ulcers, infections and the like as described by Ellis in U.S. Pat. No. 4,019,510. Means have been provided to measure resistance of skin areas to determine those most susceptible to treatment by light electrical or magnetic energy, as described by Tomecek in U.S. Pat. No. 4,112,923.
The prior devices administer electrical energy at a variety of frequencies and in different patterns. Typical of these is the system disclosed by Rossen in U.S. Pat. No. 4,989,605 which applies a carrier signal to the skin through an electrode. The signal is in the form of D.C. bursts in the frequency range of 10,000 to 19,000 Hz which is modulated on and off at a lower frequency. Other typical devices include the microprocessor controlled device for applying a low frequency pulse train and a modulated high frequency pulse train to a patient through an electrode as disclosed by Padjen et al in U.S. Pat. No. 4,719,922, a device in which a constant current square wave signal is directed into the body between two electrodes as described by Hudleson et al in U.S. Pat. 4,232,680 and a device in which a high frequency low amperage current is applied to a body through an electrode as described by Liss et al in U.S. Pat. 3,902,502.
These prior art devices, although effective to an extent, generally simply provide treatment and later evaluate the effectiveness of the treatment subjectively, through lower perceived pain or physiological changes measured in muscles or nerves. In order to obtain optimum application of electrical energy and optimum results, the results of the stimulation should be measured concurrent with the treatment. Thus, there is a continuing need for devices that measure effectiveness during treatment, so that the treatment intensity, duration, location, etc. can be varied as necessary for optimum results.